Visual Studio Load Test Virtual Users Simulation

I'm currently working on writing a load testing application that takes advantage of Load Test using Visual Studio 2010. The load test will simulate 20 users on the same machine, and I need some data to be shared in-memory between all simulated users.

I was suprised I couldn't find documentat开发者_开发问答ion answering the following question:

What seperates each virtual user's running context from the other? Does each virtual user runs the tests in its own process? Maybe in its own app domain? Or just on its own thread? I need to know because if each user is running tests in its own process then all the in-memory cache isn't shared and is created for each user instead of one time for all of them, which is bad for me.

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You can use Process Explorer (http://technet.microsoft.com/en-us/sysinternals/bb896653 it’s an advanced version of Task Manager) to get the answer.

Run a Visual Studio Load test and open Process Explorer. Check for new processes are being created. Then find the Visual Studio process and double-click. Then select the .NET Performance tab and it should show the list of all AppDomains in the process.

Incidentally, today we released a Fiddler Extension for load testing called StresStimulus - http://stresstimulus.stimulustechnology.com. Where we keep all virtual users on different threads in the same process.

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This is the closest to an answer that I have found so far.

http://blogs.msdn.com/b/billbar/archive/2007/06/13/coded-web-tests-and-web-test-plug-ins-should-not-block-the-thread.aspx

The answer being that there is a single process per machine doing the load tests, multiple threads are used, but the virtual users are "optimised" to work many per thread.

With regards to what you are wanting to do, creating a static class with a static constructor will get a shared block of memory between all virtual users. The caveat being that this is a multithreaded environment and the appropriate caution should be taken with your code.